Air in homes or in business workplaces typically includes a colloid suspension of smoke particles, plant pollens, mold spores, and dust particles. Cigarette smoke suspended in the air of a home or a workplace, commonly known as secondhand smoke, is widely suspected as being a carcinogen. Pollen and mold spores suspended in the air of a home or a workplace are common allergens which may cause sinusitis or hayfever, and other respiratory ailments. Dust suspended in the air may be harmful to persons in a home or workplace who have emphysema or asthma. Additionally, airborne smoke and dust tends to discolor and soil items in a home or workplace such as curtains and furniture. Thus, it is widely seen as desireable to create home and workplace environments whose air is substantially free of airborne smoke, pollen, mold spores, and dust.
Several types of apparatus for cleaning and filtering air within a home or workplace are known. Many have disadvantages. For example, free standing electric air cleaning machines, typically incorporating an air impeller and a filtering medium mounted in the path of air flow, take up useable space within a room and typically create undesirable background noise. Another air filtering device having disadvantages is a carbon filter or an electrostatic air filter which is installable as an auxiliary element of a building's central air and heating system. Such systems are mechanically complex, and are expensive to construct, maintain, and operate.
The instant inventive air filtering device overcomes such disadvantages, among others, by providing a mechanically simple air filter which is economical to construct and operate, which takes up virtually no living or working space of a home or workplace, and which creates virtually no background noise. Such benefits are obtained through the provision of a centrifugal fan having a filtering media attached thereto and disposed therearound, the centrifugal fan and filtering media assembly being attachable to and rotatable by the rotor plate of a common ceiling fan; such ceiling fan having its fan blades removed.